Method for treating synthetic linear polyesters fibers and film in the vapor phase to improve the dyeability and to heat set said polyesters

ABSTRACT

A method is provided for improving the dyeability and for heat setting synthetic linear polyesters, wherein the polyester in fibrous or film form is contacted with a vapor of a monocyclic or bicyclic halogenated aromatic hydrocarbon for 10 4 to 20 seconds. The halogenated aromatic hydrocarbon is removed from the polyester after treatment. The polyester fibers and films treated in accordance with the method of this invention exhibits superior dyeing properties being readily dyed to deep shades in the absence of a carrier. The polyester fibers and films treated in accordance with the present invention likewise exhibit improved dimensional stability.

United. States Patent 1151 99,993

Barwick, III et al. v [451 :1 H, mm

[54] METHOD FOR TREATING SYNTHETIC [56] Y References Cited LINEARPOLYESTERS FIBERS AND I UNITED STATESPATENTS FILM IN THE VAPOR PHASE To2 999 002 9/1961 11 8/166 ayvau IMPROVE THE DYEABILITY AND To 3,512,913970 Day et al ..s/4

HEAT SET SAID POLYESTERS [72] inventors: Frederick E. Barwick, III,Charlotte; Ver- P i ary am n -Donald Levy non C. Smith, Huntersville,both of N.C.; Assistant Examiner-43. Bettis Robert W. McCullough,Riverside, Conn.; Attorney-Paul & Paul James B. Hobgood, Roxboro, N.C.

[73] Assignee: Collins 81 Aikman Corporation, New [57] ABS CT York,N'.Y. A method is provided for improving the dyeability and for heatsetting synthetic linear polyesters, wherein the polyester [22] Sept1969 in fibrous or film form is contacted with a vapor of a mono- [21]Appl. No.: 857,844 cyclic or bicyclic halogenated aromatic hydrocarbonfor 10" to seconds. The halogenated aromatic hydrocarbon is removed fromthe polyester after treatment. The polyester [52] US. Cl ..8/4, 8/179,8/8l654, fibers and films treated in accordance with the mehod of this[51] Int. Cl. ..D06.p 3/00 invemlm exhibits p r yeing properties beingreadily 581 Field of Search .s/4, 179, 165, 175, 174, 94 dyed deepShades in, the absence a carrier- The Polyester fibers and films treatedin accordance with the present inven- 7 tion likewise exhibit improveddimensional stability.

9 Claims, 2 Drawing Figures VAPORI ZOR l FRACT! ONATOR Patent ed March21, 1972 3,650,663

FREDERICK E. BARWICK VERNON 6. SMITH ROBERT w. McCULLOUGH BY JAMES B.HOBGOOD ATTORNEYS.

METHOD FOR TREATING SYNTHETIC LINEAR POLYESTERS FIBERS AND FILM IN THEVAPOR PHASE TO IMPROVE THE DYEABILITY AND TO HEAT SET SAID POLYESTERSBACKGROUND OF THE INVENTION 1. Field ofthe Invention This invention isconcerned with a method for modifying the properties of synthetic linearpolyesters. More particularly this invention is concerned with a methodfor improving the dye ability and dimensional stability of polyesterfibers and films.

2. Description of the Prior Art The synthetic linear polyesters whichare prepared from dibasic aromatic acids and glycols such as thepolyesters of the polyethylene terephthalate type possess manyproperties which make them especially valuable for employment in theform of fibers and films. However, due to a combination of the relativechemical inertness of the polyester polymers and the hydrophobic natureof the polyester polymers and the high degree of compactness of thefibers and films made from the synthetic linear polyester, considerabledifficulty is encountered in dyeing polyester fibers and films.

Various suggestions have been made to improve the dyeability of thepolyesters. One such suggestion was to dye the polyesters with dyestuffshaving a relatively small molecular size. The resultant polyesterdyeings, however, had poor fastness especially to laundering. Anadditional suggestion was to employ high temperature high pressuredyeing techniques.

, This suggestion was not satisfactory in that it required the use ofspecial'pressure dyeing apparatus, and necessitated the use of batchdyeing techniques.

An additional suggestion was to include in the aqueous dye bathcompounds referred to as carriers to assist the application of thedyestuffs ontothe polyester fibers and films. Various types of compoundswere suggested as carriers. These compounds included, for example,phenolic compounds, such as, 0' or pphenylphenol, esters such asmethylsalicylate and halogenated compounds such as the dichlorobenzenesand the trichlorobenzenes. The amount of the carriers that were addedwere dependent to some extent on the depth of the shade desired.However, the amount of the carrier that was generally employed was inthe range of approximately 10 percent by weight of the dye bath. Thecarrier dyeing technique was not satisfactory. Initially the use of thecarriers substantially increased the cost of dyeing the polyesters. Therate of dyeing was substantially improved. However, the rate of dyeingwas still relatively slow requiring approximately 60 minutes of dyeingtime for exhaustion of the dye bath under normal dyeing conditions. Thislength of dyeing time precluded the use of continuous dyeing methodswhen dyeing polyesters using the carrier dyeing technique.

Attempts have been made to improve the dyeability of the polyesters bypre-treating the polyesters before dyeing. It was reported, for example,by A. H. Brown, and A. T. Peters in American Dyestuff Reporter of Apr.22, 1968, that when polyester fibers were pre-treated with aqueousdispersions of carriers that the resulting pre-treated fibers had betterdyeability in the absence of the carrier than the untreated fibers.However, it was further reported that the pro-treated fibers did notexhibit the same dyeability as untreated fiber dyed in the presence of acarrier. Accordingly, the pretreatment with the aqueous dispersions ofthe carriers was not a satisfactory solution.

Various methods were suggested, in the prior art, wherein thesurfaces'of synthetic linear polyester fibers were made more dyeable.One such method was disclosed by D. S. Adams, U.S. Pat. No. 3,155,754,wherein the surfaces of polyester fibers were treated with semi-solventsfor the polyester to form a layer of more dyeable polyester material onthe outer surface of the fibers. The resulting fibers had a sheath-corestructure. The outer sheath of the fibers accepted the dyestuff morereadily than the untreated fibers. The

resultant dyeings were not, however, satisfactory in that the fiberswere ring dyed because of the difference in the dyeability of the sheathand the core. Fibers that are ring dyed are unsatisfactory in that asthe fiber wears or is abraded the color changes noticeably.

Another method of treating the surfaces of polyester fibers to improvetheir dyeability is disclosed by Gruschke, et al., U.S. Pat. No.3,I54,374. In the Gruschke, et al. process polyester fibers are treatedat high temperatures, for example 200 to 350 C. for short periods oftime, for example 10 seconds to 10 seconds, with certain selectedesters, ethers or ketones. Typical treating agents employed in theGruschke, et al. process are for example, sebacic acid dimethylester,benzophenone and phenylbenzoate. The process taught by Gruschke,'et al.was not a satisfactory solution to the problems of dyeing polyesters. Atthe temperatures at which the Gruschke, et al. process was conducted thepolyesters shrunk considerably. The increase in the dyeability ofpolyester fibers was at best only a surface effect which caused the"ringdyeing of the fibers which had the well known disadvantages noted above.In addition, the Gruschke, et al. process at best only increased therate of dyeing the pro-treated polyesters to that obtainable with theuse ofa carrier which limited the dyeing of the polyesters to the batchtype dyeing rather than continuous methods of dyeing.

Despite all of the various methodssuggested in the prior art forimproving the dyeability of the polyesters, it was still not possible tosatisfactorily obtain printed polyester fabrics in relatively heavyshades, especially on heavy weight materials. The inability tosatisfactorily print heavy weight polyester fabrics considerably limitedthe use of the polyester fibers in certain high volume fabrics, such as,printed carpeting.

An additional area wherein some difficulty was encountered with thepolyester fibers was the manufacture of texturized yarn and fabrics.Texturized yarns and fabrics are employed in order to obtain specialeffects, such as, high bulk or to impart elastic properties to thefabrics. Various well known methods are employed to make texturizedyarns, such as, twist-untwist, false twisting, knit deknit, and soforth. In the various processes the yarn or fabric are heat set at leastonce in order to set the texturized effect in the yarn or fabric. Theheat setting step has caused considerable problems especially withregard to both the cost and the uniformity of the treatment. Dependingon the process employed, the yarn may be subjected to several coneingsand also to batch type autoclaving for extended periods of time whichincrease the process costs. The ends comprising a given fabric mayreceive substantially different treatment in heat setting. Thedifference in the treatment causes variations in both the dyeability andthe appearance of the final fabric. The variations in the heat settreatment cause defects in the finished produce as barre marks andunlevelness in the dyeing of the fabrics.

It is an object of the present invention to overcome the forementionedproblems and difficulty encountered in the prior art methods.

It is a further object of this invention to provide a process forimproving the dyeability of synthetic linear polyester fibers and films.

It is a still further object of this invention to provide a method ofpre-treating synthetic linear polyester fibers and films so that theycan be dyed in the absence of a carrier in a time which is substantiallyless than that required for the dye ing of untreated polyester in thepresence of a carrier.

It is an additional object of this invention to provide a method fordimensional stabilizing texturized yarns and fabrics comprised ofsynthetic linear polyester fibers in which the treatment issubstantially uniform to all of the fibers comprising the fabric or yarnand is conducted in a short period of time in a continuous manner.

Other objects and advantages of the present invention will becomefurther apparent from a review of the attached draw ing and a reading ofthe specification and subjoined claims.

SUMMARY OF THE INVENTION The objects of this invention have beenachieved by providing a method wherein the synthetic linear polyesterfibers or films are treated with a vapored halogenated aromatic forabout l to 20 seconds and then the halogenated aromatic hydrocarbon isextracted from the polyester.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration ofan apparatus for treating synthetic linear polyesters in the vaporphase.

FIG. 2 is a pictorial illustration of a polyester yarn taken asindicated by the dotted area 2 on FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The synthetic linear polyesterswhich are preferably treated in accordance with the present inventionare the condensation polymerization products of dicarboxylic acids andpolyhydric alcohols. The repeating structural units of the polymer chaininclude at least one divalent carbocylic ring containing at least sixcarbon atoms which is present as an integral part of the polymer chainand have a minimum of four carbon atoms between the points of attachmentof the ring in the polymer chain. The preferred synthetic linearpolyesters are of the polyethylene terephthalate type. Other types ofpolyesters are likewise employable such as those obtained bypolymerizing a dicarboxylic acid such as terephthalic acid,bromoterephthalic acid, 4, 4-benzophenonedicarboxylic acid and so forthwith glycols such as those of the .formula HO(Cl-l ),,OH wherein, n is awhole number from 2 to 10, diethylene glycol, neopentylene glycol andthe like.

The synthetic linear polyesters that are treated may be found in variousphysical shapes. The polyesters may, for example, be treated in the formof continuous films from about 0.5 to 20 mils thick. The polyesters mayalso be treated in the fibrous form. When referring to fibers and to thefibrous form this is intended to include, unless otherwise indicated,fibers per se such as continuous filaments and also to include fiberswhich have been manufactured into yarns and fabrics. With regard to thefabrics the terminology fabrics includes woven fabrics, knitted fabricsand nonwoven materials. When referring to yarns this is intended toinclude filament yarns, spun yarns, slit yarns and fibrillated yarns.The yarns and fabrics that are treated according to this inventionpreferably consist of only polyester fibers. However, it is possible totreat polyesters in blends with other fibers by the present inventionproviding the other fibers are not adversely affected.

The halogenated aromatic hydrocarbons which are employed in the presentinvention are monocyclic hydrocarbons. The halogenated aromatichydrocarbons are represented by the formula wherein R, and R are thesame or different and represent hydrogen. an alkyl having one to fourcarbon atoms such as methyl, ethyl, n-propyl, isopropyl, and n-butyl oran alkenyl having two to four carbon atoms such as vinyl, l-propenyl andZ-butenyl. R is a lower alkylene having one to four carbon atoms such asmethylene, ethylene, propylene and butylene.

The symbol X in the above formula stands for a halogen such as fluorine,chlorine, bromine or iodine, n is a whole number from 1 to 3 and when nis 2 or more X can stand for the same or different halogens.

The halogenated aromatic hydrocarbon employed in the method of thepresent invention should have a boiling point below the shrink 0rdecomposition temperature of the polyester to be treated. The boilingpoint should be at least C. and more preferably at least 20C. lower thanthe shrink or decomposition temperature of the polyester to be treated.Since most polyesters start to exhibit shrinking at temperatures ofabout 23()260 C., the upper limit on the boiling point should be 220-250C. depending on the particular polyester being treated.

lt is, however, of considerable advantage to use lower boilinghalogenated aromatic hydrocarbon solvent since this gives a wide rangeof control over the process condition that maybe employed. Thehalogenated aromatic hydrocarbon should advantageously be substantiallyanhydrous. However, it can contain minor amounts of water and will tendto pick up small amounts of water from the polyester being treated. Thewater can be easily removed from the treating medium when it is purifiedsince the halogenated aromatic hydrocarbons are water immiscible.

Blends of halogenated aromatic hydrocarbons can be employed if desired,however, it is preferable to employ a single compound as it facilitatesthe treatment step and the recovery of the halogenated aromatichydrocarbon as will be more specifically set out below.

The preferred halogenated aromatic hydrocarbons for employment in thisinvention are represented by the formula wherein X is chlorine orbromine and n is l or 2. The monohalogenated benzane compounds are oneof the preferred classes of compound because of their relatively lowboiling points. Monochlorobenzene, because of its relatively low boilingpoint and its relatively low cost, is an excellent compound for use inthis process. When higher boiling points are required, compounds such asbromobenzene and iodobenzene can be employed to some advantage.

The dihalogenated benzenes are also quite useful in the process of thepresent invention and are one of the preferred class of compounds. Allof the isomers of the dihalogenated benzenes such as the dichloro, thedibromo and the diiodo benzenes give excellent results. The mixeddihalogenated compounds, such as mand pbromochlorobenzenes and theiodobromodenzene compounds, such as the ortho and meta isomers arelikewise useful in the present invention.

The trihalogenated benzenes, such as the l, 2, 3- trichloro. l, 2, 4-trichloro and the l, 3, 5- trichloro benzenes can be employed but,because of their relatively high boiling points and because of thepresence of the additional halogens, are more difficult to control inthis process ofthe present invention.

Of the compounds wherein R or R represent alkyls having one to fourcarbon atoms, by far the most important class of compounds are thehalogenated toluenes and halogenated xylenes compounds, especially themonohalogenated compounds, such as the chlorotoluenes and bromoxylenes.

Of the compounds where R is a lower alkylene and m is 2 particularattention is directed to compounds such as a chlorotoluene, aodichlorotoluene, abromotoluene and abromoo xylene.

The selection of the particular halogenated aromatic hydrocarbon isdependent on various factors such as the desired treatment temperature,cost and commercial availability of the compound, and the resultingimprovement in the properties ofthe polyester. By comparing all ofthescfactors it has been found that either mono or dichlorobenzenes areclearly the preferred compounds for employment in the present invention.

In the method of this invention the polyester material is contacted witha vapor of a halogenated aromatic hydrocarbon of the type describedabove. The polyester material is held in contact with the vapor for arelatively short period of time. Times as short as 10 seconds can beused and still obtain satisfactory results. Shorter times can also beused and some a longer treating time in order to obtain an equivalenttreatment because of the higher density of the film as compared with thefabrics. Heavy weight goods require longer treatment times than lightweight, goods. A critical factor with regard to the treatment time isthe treatment temperature at which the process is conducted. The higherthe treatment temperature the shorter the treatment times thatarerequired. A still further factor to consider is the particularhalogenated aromatic hydrocarbon thatis employed. The lower halogens,for example, chlorine are more active and the activity increases with anincrease in the number of halogenssubstituent on the compounds that areemployed.

In order to further explain the method of this invention specificreference is made to the drawings. In FIG. 1 an apparatus isschematically illustrated which is especially well suited for employmentin the process of the present invention. A continuouslength of apolyester material isfed into a vapor treating chamber 12. Thecontinuous length of material could be in the form of a film,-fabric,yarn or the like. The vapor treating chamber 12 is a closed chamberhaving upper and lower seals 14, 16 through which the polyester material7 enters and leaves the chamber 12. At the upper portion of the chamberis an. exhaust line 18 for taking off vapors. At the base of the chamber12 there is a drain line 20 for removing liquids. Inside thechamberthere is a lower guide roll 22 and a pair of upper rollers 24 which bothguide and'nip the polyester material 10 as -it passes through thechamber 12. Positioned within the chamber 12 is a pair of paralleldistributing heads 26, 28, each of which has a plurality of orfices 30.The orfices 30 on each distributing head 26, 28 are directed at theportion of the polyester material 10 passing between the distributingheads 26, 28. The halogenated aromatic hydrocarbon is heated above itsboiling point to the desired treatment temperature in the vaporizer. Thevapors are fed through the feed line 32 into each of the distributingheads 26, 28. The vapors 34 are discharged fromthe heads 26, 28 throughthe orfices 30 in each of the heads. The polyester material 10 is fedthrough the vapors 34 at a speed such that the length of exposure to thevapors 34 is in the order of 10 to 20 seconds.

In the preferred method of this invention the temperature of thepolyester material 10 as it enters the chamber 12 and the temperature ofthe vapors 34 are maintained so that the vapors 32 will condense on thesurface of the material being treated. As shown in FIG. 2 thehalogenated aromatic hydrocarbon should preferably condense in a thinfilm 36 on the surface of the polyester yarn 38. As the polyestermaterial 10 is fed through the vapors 34, it will be heated by thevapors 34. in the optimum operating conditions the polyester material 10will gradually be heated by the vapors 34 to a temperature above theboiling point of the halogenated aromatic hydrocarbon, whereupon thefilm ofliquid 36 is volatilized off the treated polyester material 10.

The process of the present invention can also be conducted so that thereis no condensation at all on the polyester 10 during treatment, that is,it can be conducted completely in the vapor phase.

After treatment in the chamber 12 the halogenated aromatic hydrocarbonis removed from the polyester material 10. One of the better ways ofremoving the treating media is to pass the polyester through a vacuumdryer 40. The vacuum dryer removes the residual treating agent from thepolyester material 10. The vapors are exhausted from the vacuum dryerand which has a boiling point which is substantially different andpreferably lower than the boiling point of the halogenated aromatichydrocarbon in order to facilitate the separation and recovery of thematerials. Solvents which have proven to be especially valuable asextraction media are the halogenated aliphatic hydrocarbons, such asmethylene chloride, trichloroethylene, l, l, ltrichloroethane,perchloroethylene and mixtures thereof.

The synthetic linear polyesters treated in accordance with the presentinvention are equivalent to the untreated polyesters with regard totheir physical properties, such as tensile strength. There is nosubstantial gain or loss in weight due to the treatment of the presentinvention. However, the polyesters treated in accordance with thisinvention can readily be dyed in the absence ofa carrier at normalpressures. The most suitable dyestuffs for dyeing the polyesters treatedin accordance with this invention are the dispersed dyestuffs whichinclude dyestuffs in the azo, azomethine, nitroarene and anthraquinonechemical classes. Surprisingly, the dyeing, even though conducted in theabsence of a carrier and at normal pressures, can be conducted in aconsiderably shorter time with a 75 percent reduction in dyeing timebeing easily obtained. lt should'be further noted that the dyeing is notsurface dyeing but rather the fiber is dyed to its entire volume and thedyeing is level. The exhaustion of the dyestuffs from the dye bath isalmost [00 percent. The treated polyester can be dyed continuouslybecause of the possibility of employing relatively short dyeing timesusing, for example, pad steam continuous type dyeing machines. It isalso possible to print the polyesters, even the heavyweight polyesterssuch as carpeting, and obtain sharp accurate prints in relatively deepshades which exhibit excellent fastness.

The polyester fibers and films which are heat set according to themethod of this invention have a uniform set which is resistant even totreatment in boiling water. The heat setting of the polyester isrelatively simple to control so as to obtain reproducible results oneach run. In addition, all the ends of a given warp can be treated atthe same time so as to have uniform treatment across the width of thefabric. The heat setting is completed in a matter of a few minutesrather than hours as required with the conventional heat setting methodsand with a minimum amount of labor being involved.

In order to illustrate the present invention, below are examples showingtypical methods of employing the present invention. Percentages referredto in the examples are to be considered the percentages by weight notvolume unless otherwise indicated.

EXAMPLE l A 4-ounce -square fabric made of spun polyethyleneterephthalate fiber, commercially known as Dacron, was placed in achamber saturated with vapors of chlorobenzene at 132 C. for a period ofIO seconds. The fabric was then immersed in three separate portions ofl, l, ltrichloroethane in order to remove the chlorobenzene andsubsequently dried at C. for 30 seconds in order to remove the residuall, l, ltrichloroethane.

The treated fabric was dyed at 99-l00 C. for l hour in a 30:1 liquorratio dyebath of the following composition:

1.0 percent OWF Disperse Blue 27 0.5 percent OWF Sodium acetate Afterdyeing the fabric was washed with water at 30 C. in order to remove anyunfixed dyestuff. The fabric was dyed a full shade of blue.

A sample offabric as described above which was not treated with vaporsof chlorobenzene was dyed at 99100 C. for 1 hour in a 30:1 liquor ratiodyebath of the composition described above. After dyeing the fabric waswashed with water at 30 C. in order to remove any unfixed dyestuff. Thefabric was stained a pale shade ofblue.

Another sample of fabric as described above which was not treated withvapors of the chlorobenzene was dyed according to the previouslydescribe procedure with a dyebath ofthe following composition:

1.0 percent OWF Disperse Blue 27 0.5 percent OWF Sodium acetate 10.0percent OWF Emulsified Biphenyl carrier After dyeing the fabric waswashed with water at 30 C. in order to remove any unfixed dyestuff. Afull shade of blue almost equal in depth and shade to the sample whichwas treated with chlorobenzene vapors was obtained.

EXAMPLE 2 The procedure described in Example 1 was repeated with thesample being treated with vapors of various other halogenated aromatichydrocarbons as noted below:

Halogcnaictl Aromatic Sample llytlrocarhon Color Bromoben/ene [)eeplevel blue I or. tr. ltriclllorotoluene As abote 3 u. o. -dichluro-p-x|enc As above 4 1. 2tl|chlorohen1cne Deep blue.

Some shrinkage EXAMPLE 3 The general procedure disclosed in Example 1was repeated but different commercially available polyethyleneterephthalate fibers and different dyestuffs were employed.

Color I Polyester Fiber Disperse Dyestuff .Knit stocking samples made of150 denier polyethylene terephthalate fiber, commercially known asFortrel, were treated with chlorobenzene vapors at 132 C. for secondsand the chlorobenzene was removed in a series of three extractions withl, l, ltrichloroethane and the samples were dried at 90 C. for secondsto remove the residual 1, l, 1- trichloroethane. The treated samples, ablank, and a sample which was only subjected to extraction with the 1,l, ltrichlorobenzene were each dyed at 99l00 C. for one-half hour in a30:1 liquor ratio dyebath containing 1.0 percent OWF Cl Disperse Blue 270.5 percent OWF Sodium acetate After dyeing the samples were washed withwater at 30 C. to remove any unfixed dyestuff. The shades ofthe dyeingwere as follows:

Solvent extracted Light blue stain.

only slightly more le\el than Sample No. 2

Sample l-3 were deknitted and the yarns were boiled in water forone-fourth hour. Sample 1 retained the crimp while Sample 2 and 3 didnot retain the crimp.

EXAMPLE 5 A 2.0-mil film made of polyethylene terephthalate,commercially known as Mylar, was placed in a chamber saturated withvapors of chlorobenzene at 132 C. for a period of 5 seconds. The filmwas then immersed in three separate portions of l, l, ltrichloroethanein order to remove the chlorobenzene and subsequently dried at C. for 30seconds in order to remove the residual 1, 1,

EXAMPLE 6 A 2.0-mil film made of polyethylene terephthalate, commereially known as Mylar, was placed in a chamber with vapors ofchlorobenzene at 148 C. for a period of 5 seconds. The sample uponremoval from the chamber was free of chlorobenzene. Alternatively,samples which may contain chlorobenzene can be immersed in l, l,ltrichloroethane to extract the chlorobenzene. The treated film was dyedatv 99-l00bL C. for one-half hour in a 30:1 liquor ratio dyebath of thefollowing composition:

1.0 percent OWF Disperse Yellow 54 0.5 percent OWF Sodium acetate IAfter dyeing the fabric was washed with water at 30 C. in order toremove any unfixed dyestuff. The fabric was dyed a full shade of blue.

EXAMPLE 7 The general procedure disclosed in Example 6 was repeated with2.0-mil polyethylene terephthalate film, commercially known as Mylar,but different halogenated aromatic hydrocarbons, temperatures anddyestuffs as noted below were employed.

EXAMPLE 8 A tufted carpet sample made of polyethylene terephthalatefiber, commercially known as Encron, was placed in a chamber saturatedwith vapors of chlorobenzene at 132 C. for a period of 10 seconds. Thesample then immersed in three separate portions of 1, 1, 1-trichloroethane in order to remove the chlorobenzene and subsequentlydried at 90 C. for 30 seconds in order to remove the residual l, 1,ltrichloroethane.

The treated sample was dyed at 99l00 C. for 1 hour in a 25:1 liquorratio dyebath of the following composition:

1.0 percent OWF Disperse Red 60 0.5 percent OWF Sodium acetate Afterdyeing the sample was washed with water at 35 C. in order to remove anyunfixed dyestuff. The carpet was dyed a full bright shade of red.

A sample of carpet as described above which had not been treated withchlorobenzene vapors was dyed at 99-l00 C. for 1 hour in a :1 liquorratio dyebath of the following composition:

l.0 percent OWF Disperse Red 60 0.5 percent OWF Sodium. acetate 10.0percent OWF Emulsified biphenyl carrier After dyeing the sample waswashed with water at 35 C. in order to remove any unfixed dyestuff, Thecarpet was dyed blue but was not as bright nor as full as the samplewhich had been treated with chlorobenzene vapors.

EXAMPLE 9 It The method for improving the dyeability and heat settingsynthetic linear polyester which comprises: contacting said polyesterwith a vaporized member selected from the group consisting of ahalogenated aromatic hydrocarbon of the formula 3)m-ln wherein R,Eriii'rfi'oi different and each stands for a member selected from thegroup consisting of hydrogen,

alkyl having one to four carbon atoms and alkenyl having two to fourcarbon atoms. R is an alkylene having one to four carbon atoms. X is ahalogen selected from the group consisting of fluorine, chlorine.bromine and iodine, n is a whole number from l-3, m is a whole numberfrom l-2 and mixtures of said halogenated aromatic hydrocarbons,removing said member from said polyester and thereafter dyeing saidpolyester.

2. The method according to claim 1 wherein said polyester is contactedwith a vapor of said halogenated aromatic hydrocarbon which is heated toa temperature above the boiling point of the halogenated aromatichydrocarbon but below the shrink and decomposition temperature of thepolyester.

3. The method according to claim 2 wherein said halogenated aromatichydrocarbon is represented by the formula wherein X is chlorine orbromine and n is a Whole number from 1 and 2.

4. The method according to claim 3 wherein X is chlorine.

5. The method according to claim 2 wherein said halogenated aromatichydrocarbon is heated to a temperature relative to the temperature ofsaid polyester such that the halogenated aromatic hydrocarbon vaporscondense on said polyester.

6. The method according to claim 2 wherein said halogenated aromatichydrocarbon is heated to a temperature relative to the temperature ofsaid polyester such that the halogenated aromatic hydrocarbon condenseson said polyester in a thin film and continuing heating said polyesteruntil it is above the boiling point of the halogenated aromatichydrocarbon, thereby causing said film to volatilize off said by the

2. The method according to claim 1 wherein said polyester is contactedwith a vapor of said halogenated aromatic hydrocarbon which is heated toa temperature above the boiling point of the halogenated aromatichydrocarbon but below the shrink and decomposition temperature of thepolyester.
 3. The method according to claim 2 wherein said halogenatedaromatic hydrocarbon is represented by the formula wherein X'' ischlorine or bromine and n'' is a whole number from 1 and
 2. 4. Themethod according to claim 3 wherein X'' is chlorine.
 5. The methodaccording to claim 2 wherein said halogenated aromaTic hydrocarbon isheated to a temperature relative to the temperature of said polyestersuch that the halogenated aromatic hydrocarbon vapors condense on saidpolyester.
 6. The method according to claim 2 wherein said halogenatedaromatic hydrocarbon is heated to a temperature relative to thetemperature of said polyester such that the halogenated aromatichydrocarbon condenses on said polyester in a thin film and continuingheating said polyester until it is above the boiling point of thehalogenated aromatic hydrocarbon, thereby causing said film tovolatilize off said polyester.
 7. The method according to claim 1wherein the polyester after treatment with and removal of thehalogenated aromatic hydrocarbon is dyed.
 8. A polyester having improveddyeability prepared by the method of claim
 1. 9. The dimensionalstabilized polyester prepared according to the method of claim 1.